Handheld electronic devices, such as mobile phones, personal digital assistants (PDAs), pocket personal computers (PCs), gamepads, and camcorders, generally have multiple buttons that allow one to interface with the device by inputting information. The capabilities of these devices are increasing while the size and weight are decreasing to enhance their portability. For example, mobile phones, in addition to their traditional role as voice-communication devices, now include functions traditionally associated with other devices, such as electronic games, PDAs, and digital cameras.
To permit effective interaction with handheld devices, the handheld devices typically provide visual and aural cues or feedback. In addition to conventional visual and aural feedback, some of these devices attempt to enhance the effectiveness of device feedback by providing tactile cues or feedback. Some devices utilize structural tactile methods. One such example is to provide raised surfaces on the input surface, e.g., a keypad, of the device. Such methods, however, are inherently static and thus cannot offer effective tactile feedback.
Active methods of providing tactile feedback include incorporating a pager motor into handheld electronic devices. Such a method of providing haptic cues, however, generally vibrates the entire device.
The size of the input area in a handheld device limits the area used to provide haptic feedback. Furthermore, the amount of physical contact with the input area is generally limited to a small surface of a finger while inputting information to the device. Moreover, the act of inputting information to the device involves applying pressure against the input surface, thereby attenuating the haptic feedback conducted through the button or keypad. Thus, the number and effectiveness of haptic cues that can be conveyed in such a manner is very limited.